Enhancing pedotransfer functions with environmental data for estimating bulk density and effective cation exchange capacity in a data‐sparse situation

Soil bulk density (BD) and effective cation exchange capacity (ECEC) are among the most important soil properties required for crop growth and environmental management. This study aimed to explore the combination of soil and environmental data in developing pedotransfer functions (PTFs) for BD and ECEC. Multiple linear regression (MLR) and random forest model (RFM) were employed in developing PTFs using three different data sets: soil data (PTF‐1), environmental data (PTF‐2) and the combination of soil and environmental data (PTF‐3). In developing the PTFs, three depth increments were also considered: all depth, topsoil (<0.40 m) and subsoil (>0.40 m). Results showed that PTF‐3 (R²; 0.29–0.69) outperformed both PTF‐1 (R²; 0.11–0.18) and PTF‐2 (R²; 0.22–0.59) in BD estimation. However, for ECEC estimation, PTF‐3 (R²; 0.61–0.86) performed comparably as PTF‐1 (R²; 0.58–0.76) with both PTFs out‐performing PTF‐2 (R²; 0.30–0.71). Also, grouping of data into different soil depth increments improves the estimation of BD with PTFs (especially PTF‐2 and PTF‐3) performing better at subsoils than topsoils. Generally, the most important predictors of BD are sand, silt, elevation, rainfall, temperature for estimation at topsoil while EVI, elevation, temperature and clay are the most important BD predictors in the subsoil. Also, clay, sand, pH, rainfall and SOC are the most important predictors of ECEC in the topsoil while pH, sand, clay, temperature and rainfall are the most important predictors of ECEC in the subsoil. Findings are important for overcoming the challenges of building national soil databases for large‐scale modelling in most data‐sparse countries, especially in the sub‐Saharan Africa (SSA).     

Comparative efficacy assessment of pentamidine isethionate and diminazene aceturate in the chemotherapy of Trypanosoma brucei brucei infection in dogs

The chemotherapeutic efficacy of diminazene aceturate (Berenil)--a standard veterinary trypanocide and pentamidine isethionate (PMI)--a human trypanocide was compared in dogs experimentally infected with Trypanosoma brucei brucei. Also, the activities of the drugs on some serum liver enzymes were evaluated before and after treatment to ascertain the relative safety of the drugs. Fifteen local dogs (mongrels) were used for the study. Three of the dogs were uninfected controls, and twelve were infected with a stock of T. brucei brucei. Three of the infected dogs were untreated controls, three were given diminazene aceturate (DA) at 7 mg/kg body weight intramuscularly (i/m), another three received pentamidine isethionate (PMI) at 4 mg/kg i/m on days 14, 17, 19, 27, 29, and 31 post infection (PI) and the remaining three dogs were also given same dose of PMI on days 14, 16, 18, 20, 22, 24 and 26 PI. Both trypanocides effectively cleared the parasites from the blood of the infected treated dogs. However, the infection subsequently relapsed at day 42 PI in one of the dogs in the DA treated group which later died at day 70 PI. Relapse infection was not recorded with the PMI treated groups although two dogs died in the PMI treated group II (treatment at days 14, 17, 19, 27, 29, and 31 PI) without showing relapsed parasitaemia. The packed cell volume (PCV), red blood cell (RBC) count, and haemoglobin (Hb) level which decreased significantly following infection, were reversed by the trypanocidal treatment. The reversal in the red cell values was faster in the PMI treated groups than in the DA treated group. The serum alkaline phosphate (SAP), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) levels increased following infection and drug administration. The increase in the enzyme levels was greater in the DA treated groups than PMI treated groups. It was thus concluded that PMI given at 4 mg/kg i/m at days 14, 16, 18, 20, 22, 24, and 26 PI constituted a safe and efficient trypanocide and exhibited a superior trypanocidal action than DA in T. brucei brucei infected dogs.     

Milk Production by Agropastoral Red Sokoto Goats in Nigeria

The mild yield characteristics of smallholder agropastoral Fulani Red Sokoto goats were evaluated using records obtained from a total of 92 does in 6 herds, collected over a 2-year period. The results indicated that the total yield was 79.8±3.2 kg, the daily yield 0.66±0.03 kg, the peak yield 1.21±0.07 kg and the day of peak production 28.7±2.1 day of lactation. The milk yield characteristics were highly variable with a coefficient of variability of 38.6% to 69.8%. The characteristics were significantly (p<0.01–0.05) influenced by herd, season, parity and litter size of the dam. Highly positive and significant (p<0.01) correlations (r = 0.66–0.99) existed between the total yield and the average daily yield, peak yield, initial yield and day 120 yield. A negative and significant (p<0.05) correlation (r = –0.33) was observed between the peak day and the initial yield. The non-homogeneity of the milk yield characteristics in Red Sokoto does suggests the possibility of improving their daily productivity by selection of high yielding does. Selection for higher initial milk yield may also improve other milk yield characteristics.     

Manipulation of sowing dates for the control of bacterial blight of sesame (Sesamum indicum L.) induced by Xanthomonas campestris pv. sesami (Sabet & Dowson) dye

The effect of manipulating sowing dates on the incidence and severity of bacterial blight of 10 sesame varieties was investigated at Samaru, Zaria, in pot and field trials conducted during the 1983 and 1984 wet seasons (June–September). Late (August) sowing reduced plant growth and yield without a significant effect on either the incidence or severity of the disease. The number of leaves shed was, however, significantly increased with late sowing while the interaction between sowing dates and varieties was also highly significant. Symptoms appeared earlier and secondary spread in the field was faster with early (June) sown crops.